Disease-modifying Therapies for Multiple Sclerosis
Disease-modifying Therapies for Multiple Sclerosis
Multiple sclerosis (MS) is the most common cause of neurological disability in young people in Europe and North America. It is also unpredictable, particularly in the early stages of the most common clinical presentation – namely relapsing, remitting MS (RRMS). Although the risk of having further clinical episodes after a single clinical event – usually referred to as a clinically isolated syndrome (CIS) – is higher if the cranial magnetic resonance scan (MRI) demonstrates a number of high signal lesions,1 it is difficult to define risk precisely for any individual.
Similarly, although we know the risk factors for poor prognosis – including a high relapse rate early in the disease course, being male, having early progression, early ataxia and motor disturbance – it is still difficult to translate this populationderived information to a single person with MS in the outpatient clinic.
Why is it important to consider prognosis in MS? We are moving into an era of tailored treatments, so that in a disease with considerable heterogeneity we will need to adjust therapies to match the individual concerned. The availability of treatment choice provides the option of a more patient-centred service. Another reason to tailor treatments is that emerging therapies seem to be more effective, and this effectiveness may not only come at higher monetary cost, but also with higher side effect risks. Individuals with MS need to have a significant say in whether they are prepared to accept higher risks for potentially higher benefits, and in order to make these judgements we need to develop a much more sophisticated ability to predict risk over short periods.
For a treatment to be truly ‘disease-modifying’, it should alter the natural history of MS over the long term. Although the term ‘disease-modifying’ is widely used – with strong encouragement from the pharmaceutical industry – there is little evidence to support true long-term effects in most products. However, recent evidence suggests that more powerful agents may indeed have such effects, although we still need long-term followup data to demonstrate convincing disease modification.
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